One Piece: Seaside System

Stranded in a world not his own, in a body not his own, Kaden finds himself stuck as a low rank marine in treacherous waters in the middle of an ocean where only the strongest can survive and a count down until a war that would shake the oceans and the very world itself erupts, where the kings of the sea will devour the chum. Gamer System. Insert. — Description from novelcodex.org